The present invention relates to a drawing processing system and more particularly, to a parallel drawing processing technique which allows a server program to be built on a multiprocessor system within a drawing server in a drawing processing system wherein drawing instructions are transmitted from at least one client program to the drawing server for integrated execution of drawing processing for the purpose of its graphics display.
Known as a distributed drawing system is such an X window system as disclosed in an article entitled "The X Window System" in an ACM Transactions on Graphics, Vol. 5, No. 2, pp. 78-109.
The known X window system, which is equipped with a drawing server for integratedly executing drawing processing of a single display screen, is a distributed drawing processing system in which drawing instructions for the display screen are transmitted from a display client program (which will be referred to as the client, hereinafter) to the drawing server for graphics display.
In the X window system, when the single drawing server is connected to a plurality of clients, independent application programs can be utilized on the single display screen at the same time. When attention is paid on one of the clients, further, the drawing instructions from the client are sequentially processed in its arrival order within the drawing server, which ensures the consistency of the graphics display.
The drawing server of the X window system has a problem that the drawing server is operated as a single thread so that, when one client transmits a large load of drawing instruction to the drawing server, the drawing server is occupied by the processing of the single client, resulting in reduction of system response.
For solving the above problem, there is suggested such a system as described in an article entitled "The Multi-Threaded X Server" of Processings, 6th Annual X Technical Conference, pp. 73-89.
In this system, when a plurality of clients are connected to a single drawing server, exclusive drawing threads are allocated to the respective clients within the drawing server so that the drawing server can process the drawing instructions of the different clients in a parallel manner.
According to this system, since the independent drawing thread is operated for each of the clients, even when one client transmits a large load of instruction to the drawing server, it can be avoided that the drawing server is occupied by the single client and excludes the other clients.
One of features of the X window system is that a communication path is established as a message stream having its sequence kept.
However, any of these known display systems has had a problem that the drawing server cannot parallelly execute the drawing commands received from the clients of application programs but executes the commands sequentially, with the result of the fact that these systems have a limit in their higher speed processing.
The latter known display system also has another problem that, though the system can perform parallel processing over drawing instructions received from different clients, the system cannot parallelly process drawing instructions received from the same client, so that, when the drawing server is built in a multiprocessor, it is difficult for the drawing server to process the drawing instructions from the single client at a high speed.